THURSDAY, April 26, 2012 (HealthDay News) -- Scientists have identified genes linked to the small stature of Western African Pygmies in Cameroon.
A large number of previous studies have pinpointed nearly 180 genes that influence height differences in European populations, but this is the first genome-wide study of genes that affect height in African pygmies.
On average, pygmy men are about 4 feet 11 inches. It hasn't been clear why pygmies are so short, and scientists have suggested a number of theories based on natural selection. For example, pygmies' small size reduced their nutritional needs, helped them better handle hot climates or enabled them to reach sexual maturity at an earlier age.
Along with identifying genes that may be responsible for pygmies' small size, this study, led by researchers at the University of Pennsylvania, also suggests that hormonal pathways and immune system regulation may have been the evolutionary drivers of pygmies' short stature.
The study appears April 26 in the journal PLoS Genetics.
"There's been a longstanding debate about why pygmies are so short and whether it is an adaptation to living in a tropical environment," senior author Sarah Tishkoff, a professor in the genetics and biology departments at Penn, said in a university news release. "I think our findings are telling us that the genetic basis of complex traits like height may be very different in globally diverse populations."
Pygmies.org has more about African pygmies.